Hard to get on plane yesterday

[Gpayne]

Not sure if I should post this here or in the OMC forum, but here goes. I've got a 90 Sunbird 17' fish and ski with a 2.3l OMC engine and a Cobra drive. Yesterday we took it out and spent the day on the lake with the whole family. When we left the dock it was myself, my wife, and our 4 year old. The boat jumped up on plane no problem and ran great. We went over to the state park and docked while we spent a few hours on the beach with the kids. Afterward we wend back out and did some tubing, but the boat didn't want to plane out. I can understand that since we were towing a tube, and the water was kinda choppy with the wind blowing steady all day and plenty of wakes from other boats. It would come up to around 4000 rpm's at WOT and just plow water with the bow in the air. I double checked that it was trimmed all the way down and it was. After we put the tube away and dropped off the rest of the fam at the state park, we headed back to the dock, again just the wife, the kid, and I, and it still wouldn't plane out right. I got it up on plane once, but it took a few minutes of running at WOT before it did. Once it planes out, the rpm's go up like usual, and I cut the throttle back to cruising speed and trim it up till I find the happy medium. It just took forever to come up even though earlier in the day when we left the dock it came up just fine. The engine never ran bad or anything, no missing or coughing or bogging, just seemed like it was under a tremendous load until it came up on plane. Please forgive me, I don't know the size of the prop. I think it's a 13 3/8x15p, but I can't remember. I do know its aluminum and it looks like the PO took a sander or buffing wheel to it to clean it or work out some nicks or something. I'm wondering if he didn't screw it up. Anyway, I'm bugging over it, so I figured I'd ask for some advice from y'all. Thanks guys

P.S. I did notice that when it does plane out, at WOT it'll turn around 5,500 rpm's and run about 35 mph.

 

[series60]

Re: Hard to get on plane yesterday

Not sure if I should post this here or in the OMC forum, but here goes. I've got a 90 Sunbird 17' fish and ski with a 2.3l OMC engine and a Cobra drive. Yesterday we took it out and spent the day on the lake with the whole family. When we left the dock it was myself, my wife, and our 4 year old. The boat jumped up on plane no problem and ran great. We went over to the state park and docked while we spent a few hours on the beach with the kids. Afterward we wend back out and did some tubing, but the boat didn't want to plane out. I can understand that since we were towing a tube, and the water was kinda choppy with the wind blowing steady all day and plenty of wakes from other boats. It would come up to around 4000 rpm's at WOT and just plow water with the bow in the air. I double checked that it was trimmed all the way down and it was. After we put the tube away and dropped off the rest of the fam at the state park, we headed back to the dock, again just the wife, the kid, and I, and it still wouldn't plane out right. I got it up on plane once, but it took a few minutes of running at WOT before it did. Once it planes out, the rpm's go up like usual, and I cut the throttle back to cruising speed and trim it up till I find the happy medium. It just took forever to come up even though earlier in the day when we left the dock it came up just fine. The engine never ran bad or anything, no missing or coughing or bogging, just seemed like it was under a tremendous load until it came up on plane. Please forgive me, I don't know the size of the prop. I think it's a 13 3/8x15p, but I can't remember. I do know its aluminum and it looks like the PO took a sander or buffing wheel to it to clean it or work out some nicks or something. I'm wondering if he didn't screw it up. Anyway, I'm bugging over it, so I figured I'd ask for some advice from y'all. Thanks guys

P.S. I did notice that when it does plane out, at WOT it'll turn around 5,500 rpm's and run about 35 mph.

First off I think the 5500 WOT is a bit much. The planing issue may be due to water soaked flotation foam in the hull. Can you access the hull from a deck plate or other access point to inspect for water soaked flotation?

 

[oldjeep]

Re: Hard to get on plane yesterday

Was there any water in the bilge when you took the boat out of the water?

 

[Another retired guy]

Re: Hard to get on plane yesterday

Agree the 5500 is high. It sounds as though it is a prop issue, but if so the question is why did it plane ok earlier in the day. Is the boat trailered? Were you able to check the drive? Maybe some damage occurred during the day?
If everything looks ok you may want to start a new thread in the "prop questions" forum - the folks there will know if that's the correct prop for your boat.

 

[Gpayne]

Re: Hard to get on plane yesterday

There was some water in the bilge when I took the boat out, but not much. Maybe a couple of pints. I figured it was from swimmers and tubers coming in all day. Last time I had it out I didn't get any water in the bilge. Next time I'm going to have my BIL drive and I'm gonna watch really close for leaks. As for the foam, I can't access under the deck without removing the floor. I'm gonna go out today and inspect the prop for evidence of slipping or sheared splines. I'd love to take it out again and see what it does, but the weather's kinda sketchy today.

 

[etracer68]

Re: Hard to get on plane yesterday

I would think the 5500rpm is high, but that would also mean, that the pitch was on the low side, and the boat should have jumped on plane quicker. It also should have been on plane at 4000rpm. Seems something changed during the day, almost sounds like the drive was not all the way down. Was there water in the boat? Did you move a bunch of weight to the stern? When was the last time you put fresh fuel in?

 

[Gpayne]

Re: Hard to get on plane yesterday

I filled up with fuel Sat morning on my way to the lake. The gear consised of a cooler of drinks, the tube, and some spare life vests. Yeah it's kinda perplexing me. I have a spare 14x19p prop that I wanna try, but the weather is threatening rain and t-storms all day, so I'm gonna stay home. Even on the lake things can get dangerous pretty quick. I also wanna check for leaks. The water in the bilge is worrying me, but I'm hoping it was just from everybody coming in out of the water soaking wet.

 

[spdracr39]

Re: Hard to get on plane yesterday

Was everyone in the front of the boat in the morning and the back in the afternoon ? All that weight transfer will cause what you are describing on a smaller engine like yours especially if your have any water log problems.

 

[etracer68]

Re: Hard to get on plane yesterday

I would most likely stay home too. But you can check the drive and make sure its moving all the way down, while its on the trailer. If you had people getting in and out alot, it will bring water in. While your checking the drive up and down, take a look at the bellows too, for tears, or cracks.

 

[kawakx125]

Re: Hard to get on plane yesterday

the key here is that it was fine in the morning but not later in the day. something changed throughout the day so taking that into consideration you can potentially rule out things that usually happen over time, such as water logged foam. my guess is something in the drive system shot crap or was damaged. is it possible that your trim guage or switch messed up and you actually weren't trimming down drive? did you physically check it?

 

[Gpayne]

Re: Hard to get on plane yesterday

I checked the drive while my wife ran it up and down with the switch and it went all the way down fine. I just came back from my FIL's where I keep the boat. I checked everything I could think of as far as water entry and drive problems but I couldn't find anything. I filled up the bilge with water to check for leaks outside but couldn't find any, I ran it on muffs to look for leaks on the engine but I didn't see any, I had my FIL soak the entire outdrive with the hose while I watched for water entry but I didn't see any. Short of actually putting it in the water and checking, I'm out of ideas. The drive bellows look fine from what little bit I can see of it. The exhaust bellows has holes all the way along the bottom of it. I'm guessing by the way it looks that it was made that way. I will say that when we anchored to do some swimming, the waves were buffeting the stern and rear starboard side pretty good. I'd say they were running about 1' or so. The swimming was fine, we all wore our PFD's, but the boat did get bounced around pretty good. I'm thinking (hoping) that the water was from all the soaking people coming in and waves going down the bilge pump outlet hole. Next time I'll anchor so the stern is toward the leeward side. I also double checked the prop and it's a 13 1/4x17p 3 blade aluminum, but someones' done some work on it by the looks of it. I couldn't get any pics of it, my camera is messed up on my phone.

 

[JEBar]

Re: Hard to get on plane yesterday

the key here is that it was fine in the morning but not later in the day. something changed throughout the day

I agree .... you've already eliminated a good number of possible causes .... take the time and think back .... focus on the first time you noticed the problem, what had changed between then and the time before when it worked as it should .... it could be something as simple (as has been mentioned) as the location of people or other items in the boat .... any weight movement within the boat could be magnified by something as basic as fuel being burned .... did you notice any difference in the sound of the motor or size/shape of the wake .... something had to have changed

Jim

 

[Gpayne]

Re: Hard to get on plane yesterday

I've been doing alot of thinking about it. When we left the dock I put the cooler and all the gear in the stern and we were able to get out on plane just fine, but the water was still relatively smooth and glassy. Coming back to the dock, the boat setup was the same, but the water was alot rougher from all the wakes and the waves. I'm thinking that was the main reason for the trouble. I wish I had thought of it then, and redistributed the weight inside the boat more toward the bow. The sound of the engine never changed, it still ran smoothly, just sounded like it was under more of a load. Once it finally planed out though, it unloaded and the rpms came up just like normal.

 

[kawakx125]

Re: Hard to get on plane yesterday

the only thing you can do since you've eliminated leaks as a possibility is take it out by yourself on a calm day and see how she acts. if it jumps right up on plane you'll know it was probably a combination of water conditions and weight distribution. I have a 4.3 in an 18' BR and even then its very noticeable the difference in planing time with several people on board. i was at max capacity yesterday and it took alot longer to plane as well. you have quite alot smaller motor and that'd amplify the problem that much more

 

[generator12]

Re: Hard to get on plane yesterday

It's a long shot, but you say you "spent the day on the lake". When you started, I assume you had a full fuel tank. When you finished, I assume you didn't.

If the fuel tank is sufficiently forward (i.e., forward of the boat's center of gravity), the weight of the fuel might have offset some of the weight of the stern in the morning. Then, as the fuel quantity/weight was reduced, so would be the overall weight distribution - toward the stern.

 

[glenn property of pam]

Re: Hard to get on plane yesterday

another long shot but ive seen it happen. weeds can cause all sorts of problems with the prop efficency carrier bags and trash are even worse. if you reversed before you trailered the prop might have cleaned itself

 

[generator12]

Re: Hard to get on plane yesterday

another long shot but ive seen it happen. weeds can cause all sorts of problems with the prop efficency carrier bags and trash are even worse. if you reversed before you trailered the prop might have cleaned itself

I'll second that. I sometimes boat in a quite shallow lake near my home. I'm switching into reverse every five to ten minutes to clear weeds. And if I don't, just as Glenn says, I can run that engine through the roof and not get on plane.

 

[BF]

Re: Hard to get on plane yesterday

I have a 3.0 mercruiser. Recently I changed the lower shift cable, and once I fine tuned the cable adjustment on the water, it shifted great, and planed out and cruised fine. But it "felt" slower out of the hole and generally down on power. I had an idea of what it was so stopped and looked. Yes, I had accidently left one plug wire off the front spark plug. Snapped it on and of course it ran much better. So it reminded me (again) how well these I4's can run on 3 cylinders. I had removed the spark plugs to be able to turn the engine over by hand to align the coupler splines when I was putting the outdrive back on. So, I'd say check the wires / plugs to see if you're running on 3 cyl...